(a) Field of the Invention
The present invention relates to a liquid crystal display (LCD) module and, more particularly, to the structure of a combination switch including the LCD module.
(b) Description of the Related Art
In recent years, portable terminals, such as a portable data assistant or a mobile telephone, have been developed for achieving smaller dimensions and higher performances as well as excellent appearance using decorations. The higher performances should include higher functions of the portable terminals as well as simplification of the operation thereof. The simplification of the operations is partially achieved by large dimensions of a display module, such as an LCD module, which displays a guidance image for the operations.
In the circumstances as described above, the LCD module used in the portable terminal has increasingly larger dimensions. Among other parts of the portable terminal, the LCD module has a lower mechanical resistance against an external force, and thus is generally protected by an overcoat layer. The provision of the overcoat layer increases the thickness of the portable terminal, however. In addition, increase of the number of operations in the portable terminal may necessitate allocation of a single switch button to a plurality of functions, which complicates the operation itself of the portable terminal and confuses the user.
The display on the LCD module of the portable terminal is generally switched for providing a variety of operational information in view of the increase of the number of functions and services provided by the portable terminal. Examples of such a switching of the display for the operational information include a switching between a waiting mode at which the LCD module displays time information, residual battery power, antenna sensitivity or mode information such as a manner mode or vibration mode of the portable terminal, and a calling mode at which the LCD module displays a telephone number. The switching of the display on the LCD module is implemented by a changeover switch which switches between a plurality of installed programs.
The increase in the functions of the portable terminal necessitates an increase in the display area of the LCD module in the portable terminal. The provision of the changeover switch as well as provision of a number of other operational switches on a housing or casing of the portable terminal decreases the area of the housing to be allocated to the LCD module. Thus, a trade-off arises between a larger display area for the LCD module and the provision of a number of operational switches.
JP Patent No. 3019893 is directed to a camera having an installed zoom lens and implies a solution for the trade-off in the portable terminal as described above. The described camera includes a substrate, an LCD module formed thereon, and a changeover switch or seesaw switch mounted on the substrate for switching the zooming direction of the zoom lens. The substrate further mounts thereon a large number of electric interconnections.
The seesaw switch includes a pair of electric contacts sandwiching therebetween the LCD module and normally urged to a neutral position, and an arched lever made of a transparent material for allowing the LCD module to be observed therethrough and having a pair of protrusions which respectively abut against the electric contacts at the operating positions of the seesaw switch. The swivel axis of the lever of the seesaw switch extends parallel to the camera body or casing and overlies the center of the LCD module.
The seesaw switch effects abutment between each of the electric contacts and a corresponding one of the protrusions by a swivel operation, while allowing the zooming direction of the zoom lens to be observed on the LCD module. The LCD module is formed on a substrate, which is fixed onto the camera body, for indicating a variety of operational information including the zooming direction.
The described camera includes the lever of the seesaw switch, which also functions as a protective member for protecting the LCD module against an external force. This allows reduction of the total area for the operational switch and the LCD module, thereby solving the trade-off between the operational switches and the LCD module in the camera.
If the technique as described above is used in a portable terminal for solving the trade-off as described before, there arises a problem in that the structure of fixing the substrate mounting thereon the LCD module and the seesaw switch onto the camera body is complicated. In addition, the structure of the lever of the seesaw switch overlying the LCD module restricts the direction of the movement of the lever, which cannot be moved or slid in the direction parallel to the substrate because the sliding movement of the lever shields the end portions of the LCD module.